Method for data communication and system thereof

ABSTRACT

The present invention discloses a system and method for data communication. In the system and method for data communication, a part of communication peers in the communication system are assigned as super peers, and each super peer forwards message according to its route table. When a communication peer logs in the system, network information of the logged communication peer is saved in a super peer which is logically closest to the logged communication peer through messages forwarded among every super peer. And when an origination communication peer searches for a destination communication peer, the network information of the destination communication peer is saved in a super peer which is logically closest to the destination communication peer through the message forwarded among every super peer in super peer layer. The origination communication peer establishes connection with the destination communication peer based on the network information of the destination communication peer, and implements the data communication through the connection established.

FIELD OF THE INVENTION

The present invention relates to data communication technologies, andparticularly to, method and system for data communication employing peerto peer technology.

BACKGROUND OF THE INVENTION

At present, with development of data communication technologies,multiparty data communication for multiple communicating parties hasbeen implemented. For example, audio and video data can be transmittedamong multiple communicating parties, so an audio and video interactionamong these communicating parties is implemented.

In the multiparty data communication, network information of eachcommunicating party, such as a port number and IP address, is managed ina uniform manner. That is, the network information of everycommunicating party is stored and managed by a network informationmanagement server. In the multiparty data communication, thecommunicating parties acquire network information of each other via thenetwork information management server, and establish data connectionwith each other for data communication based on the network information.

Though data communication can be implemented in the above mentioned way,the network information of every communicating party has to been storedand managed in a uniform manner by the network information managementserver. Once the network information management server fails, a largenumber of communicating parties can not acquire the network informationof other parties, and fail to establish data connection with destinationcommunicating parties, so data communication in a large area can not beimplemented.

In addition, a relay server is also used to implement the datacommunication. Though the data communication can be implemented by therelay server relaying data, the data communication implemented by therelay server has the following disadvantages.

Since data needs to be relayed by the relay server in the datacommunication, and the relayed data usually includes large amounts ofdata, such as audio and video, the relay server needs a wide bandwidth,which increases cost of the relay server. In addition, because of thelimited bandwidth of the relay server, the relay server only supportsdata relay for a limited number of communicating parties. If the numberof communicating parties is large, a large number of relay servers willbe needed, and the cost of data communication will further be increased.Furthermore, if a relay server fails during the data communication,multiparty data communication forwarded by the relay server will beinterrupted, which results in a paralysis of data communication in acertain area.

SUMMARY OF THE INVENTION

The present invention provides a system for data communication, whichdoes not need uniform management of network information of communicatingparties, and solve the problem of being unable to implement datacommunication in a large area when a network information server fails.

The present invention provides a method for data communication, whichdoes not need uniform management of network information of communicatingparties, and solve the problem of being unable to implement datacommunication in a large area when a network information server fails.

The system for data communication including communication peers whichestablish connections based on network information and implement datacommunication through the connections, includes at least two superpeers, and

every super peer is configured to save network information of acommunication peer which is logically closest to the super peer, forwardmessages among super peers and send the network information of adestination communication peer to an origination communication peer.

The method for data communication includes:

sending, by an origination communication peer, a query for a destinationcommunication peer to a first super peer which is physically closest tothe origination communication peer;

searching a second super peer which is logically closest to thedestination communication peer from the first super peer;

sending, by the second super peer, saved network information of thedestination communication peer to the origination communication peer;

establishing, by the origination communication peer, a connection to thedestination communication peer based on the network information of thedestination communication peer, transmitting data for data communicationover the connection.

As seen from the above mentioned, network information of everycommunicating peer is saved in a super peer logically closest to thecommunication peer, so that the network information of the communicationpeers can be managed dispersedly. In such case, when a super peer savingthe network information fails, only data communication of thecommunication peers closest to the super peer is impacted, dataconnection failure of large number of communicating peers will notoccur, so the reliability of data communication will be improved. Inaddition, in the present invention, data does not need to be relayed bythe relay server. So the problem of increasing cost increase and theproblem of large-scale data communication paralysis brought by the relayserver are solved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram illustrating an exemplary structure ofthe system of the present invention.

FIG. 2 shows a flow chart of an exemplary method of the presentinvention.

FIG. 3 shows an exemplary flow chart illustrating the detailed processesin block 201 of the present invention.

FIG. 4 shows an exemplary flow chart illustrating the detailed processesin block 202 of the present invention.

FIG. 5 shows an exemplary flow chart illustrating the detailed processesin block 203 of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Description of the present invention is hereinafter given in detail withreference to the accompanying drawings and embodiments of the presentinvention.

The present invention discloses a method for data communication andsystem thereof. In the system disclosed by the present invention, somecommunication peers in communication system are assigned as super peers,and the super peers form a super peer layer. When a communication peerlogs into the communication system, the communication peer logs into thefirst super peer which is physically closest to the communication peer,and the first super peer registers network information of thecommunication peer on the second super peer whose TD is closest to thecommunication peer's ID through transmission among the super peers. Whenan origination communication peer needs to transmit data to adestination communication peer, the origination communication peer sendsa query to the super peer which is physically closest to the originationcommunication peer, the super peer searches locally, if no networkinformation of the destination communication peer is found in the superpeer, the query will be sent to another super peer whose ID is closestto the destination communication peer's ID. And the another super peerreturns the network information of the destination communication peer tothe origination communication peer, so the origination communicationpeer can establish a network connection with the destinationcommunication peer according to the network information of thedestination communication peer, and start data communication with thedestination communication peer.

The present invention is described in detail with reference to theaccompanying drawings and embodiments hereafter.

As shown in FIG. 1, in the system in accordance with the presentinvention, there are a number of communication peers used for datacommunication. And there are some super peers forming a super peer layerin the communication system shown in FIG. 1.

When a communication peer logs in the communication system, throughmessages forwarding among the super peers in the super peer layer,network information of the communication peer is saved in a super peerwhich is logically closest to the communication peer.

And when an origination communication peer searches a destinationcommunication peer, through the message forwarding among super peers inthe super peer layer, a super peer which is logically closest to thedestination communication peer returns the network information of thedestination communication peer to the origination communication peer.

In the above mentioned system, every super peer has followingproperties:

1. In order to guarantee that communication peers for data transmissioncan log in super peers, the super peer should be public network typepeer or a hybrid network address translation (Full Cone) type peer.

2. In order to improve efficiency of the communication network,bandwidth and online time length of the super peer need to be largerthan or equal to a preset bandwidth and a preset online time lengthrespectively. The preset online time length can vary according to thepractical condition. In initial stage of network construction, thepreset online time length can be relatively short; and when the networkis normally working for a long period of time, the preset online timelength should be relatively long.

Every super peer has a route table, and IDs and network information ofother super peers connected with the super peer are saved in the routetable. The network information includes network types, IP addresses andport numbers of internal networks and external networks. According to IDof logged communication peer or destination communication peer, a superpeer can search for another super peer whose ID is closest to the ID ofthe communication peer in the area of the super peer by employing theroute table. Then the super peer routes the communication to thementioned another super peer. And said another super peer also performsthe searching and routing process by using the route table in saidanother super peer, until the communication is routed to the super peerwhose ID is closest to the communication peer above mentioned.

As shown in FIG. 1, the system provided by the present invention alsocan include a center server. And the center server includes one or morethan one server used for collecting network information of every superpeer and instructing every super peer to update route tablerespectively. The system provided by the present invention also can workwithout the servers, which does not affect the implementation of thepresent invention.

A detailed description is hereinafter given to the method provided bythe present invention with reference to the accompanying drawings.

As shown in FIG. 2; the method in accordance with an embodiment of thepresent invention includes processes as follows.

According to processes in block 201, some communication peers in thecommunication system are assigned as super peers, and each super peersaves route information of the communication peers or the super peersconnected with it.

According to processes in block 202, a communication peer logs in thesuper peer which is physically closest to the communication peer. Fromthe super peer, the other super peers in the super peer layer in turnforward the network information of the communication peer to each otheraccording to the route information stored, until the network informationof the communication peer is forwarded to and recorded in the super peerwhich is logically closest to the communication peer.

According to processes in block 203, an origination communication peersends a query for a destination communication peer to the first superpeer which is physically closest to the origination communication peer.From the first super peer, other super peers in turn forward the querybased on the route information stored, until the query is forwarded tothe second super peer which is logically closest to the destinationcommunication peer. The second super peer sends the stored networkinformation of the destination communication peer to the originationcommunication peer.

According to processes in block 204, the origination communication peerestablishes a connection with the destination communication peeraccording to the acquired network information of the destinationcommunication peer, and transmits data through the connection, andimplements the data communication.

The implementation of the above processes is hereinafter described indetail with reference to specific embodiments. In the embodiments of thepresent invention, the ID is regarded as route information of everycommunication peer or super peer. The super peer which is logicallyclosest to the communication peer is the super peer whose ID is closestto the ID of the communication peer. In order to simplify thedescription of the embodiment of the present invention, the super peerwhich is physically closest to the communication peer is called aphysical super peer (PSP) of the communication peer, and the super peerwhich is logically closest to the communication peer is called a logicalsuper peer (LSP) of the communication peer.

As shown in FIG. 3, in the embodiment of the present invention, theprocesses in the block 201 in detail include the processes as follows.

According to processes in block 301, information of the communicationpeers in the network is read in turn.

According to processes in block 302, it is to determine whether thecurrent communication peer is a public network type peer or a Full Conetype peer according to the read information of the current communicationpeer; if yes, the processes in block 303 are performed; otherwise, it isto determine that the current communication peer is not a super peer,the processes in block 301 are performed to other communication peers.

According to processes in block 303, it is to determine whetherbandwidth and online time length of the current communication peer arelarger than or equal to a preset bandwidth and a preset online timelength; if yes, the current communication peer is assigned as a superpeer; otherwise, it is to determine that the current communication peeris not the super peer, and the processes in block 301 are performed toother communication peers. The preset online time length can varyaccording to a practical condition. In initial stage of networkconstruction, the preset online time length can be relatively short; andwhen the network is normally working for a long period of time, thepreset online time length should be relatively long.

As shown in FIG. 4, in the embodiment of the present invention, theprocesses in the block 202 in detail include the processes as follows.

According to processes in block 401, after logging in the communicationsystem, the communication peer logs in the PSP of the communication peerby sending a Pub message to the PSP of the communication peer, and sendsthe network information of the communication peer to the PSP.

According to processes in block 402, firstly the PSP searches locally,and determines whether the network information of the destinationcommunication peer is stored locally according to the ID in the networkinformation of the communication peer. If yes, the network informationof the communication peer is returned to the origination communicationpeer directly, and the processes are terminated; otherwise, the PSPsearches for the ID which is closest to the ID of the destinationcommunication peer from the IDs stored in the PSP, then the PSP routesthe network information of the communication peer to the third superpeer corresponding to the closest ID via forwarding a Pub message.

According to processes in block 403, the third super peer searches foran ID which is closest to the ID of the communication peer from the IDsstored in the third super peer, then the third super peer routes thenetwork information of the communication peer to the fourth super peercorresponding to the closest ID get by the third super peer viaforwarding the Pub message.

According to processes in block 404, the fourth super peer determineswhether there is an ID which is closer to the ID of the communicationpeer. If yes, the like processes in block 403 are performed until the IDwhich is closest to the ID number of the communication peer is searchedfrom IDs of all communication peers, and then the processes in block 405are performed; otherwise, the processes in block 405 are directlyperformed.

According to processes in block 405, the super peer of the presentrouting, as the LSP of the logged communication peer, stores the networkinformation of the communication peer.

As shown in FIG. 5, in the embodiment of the present invention, theprocesses in the block 203 in detail include the processes as follows.

According to processes in block 501, an origination communication peersends a query to a PSP of the origination communication peer, and thequery includes an ID of the destination communication peer.

According to processes in block 502, the PSP of the originationcommunication peer searches for an ID which is closest to the ID of thedestination communication peer from the IDs stored based on the ID ofthe destination communication peer. Then the PSP routes the query to thefifth super peer corresponding to the closest ID got by the PSP.

According to processes in block 503, the fifth super peer searches foran ID which is closest to the ID of the destination communication peerfrom the IDs stored in the fifth super peer, and then the fifth superpeer routes the query to the sixth super peer corresponding to theclosest ID get by the fifth super peer.

According to processes in block 504, the sixth super peer determineswhether there is an ID which is closer to the ID number of thedestination communication peer. If yes, the like processes in block 503are performed until the ID which is closest to the ID number of thecommunication peer is searched from IDs of all communication peers, andthen the processes in block 505 are performed; otherwise, the processesin block 505 are directly performed.

According to processes in block 505, the super peer of the presentrouting, as a LSP of the destination communication peer, returns thestored network information of the destination communication peer to theorigination communication peer.

The processes in the block 204 are described in detail hereinafter.

In embodiment of the present invention, a connection between anorigination communication peer and a destination communication peer canbe established via the following three methods.

The first method is that the connection is established via by internalnetwork direct-connections.

The origination communication peer sends a connection request to aninternal IP address and port number of the destination communicationpeer directly according to the acquired internal IP address and portnumber in the network information of the destination communication peer.And the connection request can be sent through Transfer Control Protocol(TCP) or User Datagram Protocol (UDP). In practical applications, thetwo protocols can be chosen according to practical demands. For datacommunication of voice and audio, the UDP is used preferentially; forsome application with relatively high requirement of transmissionreliability, the TCP is used preferentially. In practice, if the TCP isused preferentially to send the connection request, the UDP can befurther used to try to establish the connection while the connection cannot be established by using the TCP. Similarly, if the UDP is usedpreferentially to send the connection request, the TCP can be furtherused to try to establish the connection while the connection can not beestablished by using the UDP.

The second method is that the connection is established via externalnetwork direct-connections.

In the second method, before a communication peer logs in thecommunication system, an STUN test for network address translation isneeded. After the STUN test, the external IP address and port number ofthe communication peer can be obtained. And the communication peer addsthe acquired external IP address and port number to the networkinformation of the communication peer. In such case, the network information of the destination communication peer acquired by theorigination communication peer includes the external IP address and portnumber of the destination communication peer. Then the originationcommunication peer sends a connection request to the external IP addressand port number of the destination communication peer directly, andestablishes the connection between the origination communication peerand the destination communication peer. The detailed implementation issame as the processes of internal network direct-connection, and willnot be described in detail herein.

The third method is that the connection is established by a traversal ofUDP.

In the third method, before a communication peer logs in the system, anSTUN test is performed to acquire an external IP address, a port numberand a network type of the communication peer. In this case, networkinformation of the destination communication peer acquired by theorigination communication peer includes the external IP address, portnumber and network type of the destination communication peer. And theorigination communication peer determines a connection mode according tonetwork types of the origination communication peer and the destinationcommunication peer.

If one party of the communication is public network peer and the otherpart is Full Cone peer, the Full Cone party can require the other partyto initiate the connection. If the parties of the communication areneither the public network peer nor the Full Cone peer, the originationcommunication peer can send a traversal request to the PSP of thedestination communication peer, the PSP of the destination communicationpeer forwards the received traversal request to the originationcommunication peer and the destination communication peer respectively.Upon receiving the traversal request from the PSP of the destinationcommunication peer, the origination communication peer and thedestination communication peer respectively send UDP traversal packetsto the external IP address and port number of each other, so as toestablish the connection between the origination communication peer andthe destination communication peer.

in practical application, the above three methods can be performed atthe same time. If the connection is established successfully by any oneof the above mentioned three methods, the other two methods will not beused again. If all three methods fail, the origination communicationpeer sends a request for searching a relay seed to the super peersconnected with the origination communication peer. The super peeracquires information of the communication peer which can forward datavia a center server or other super peers, and returns the informationacquired to the origination communication peer. The originationcommunication peer establishes a relay channel based on the informationfrom the super peer, and establishes the connection with the destinationcommunication peer. If there are multiple communication peers which canrelay data, the origination communication peer can establish a number ofrelay channels based on the information of the multiple communicationpeers, and one of the relay channels is regarded as a main channel,others are regarded as backup channels. If the main channel of datacommunication is disconnected, data communication is switched to thebackup channel. In this way, the probability of unsuccessfulcommunication between the two parties brought by the quitting of a thirdparty is greatly reduced.

In practical application, when each communication peer in the systemquit or log in the system, the route table in each super peer needs tobe updated. In embodiments of the present invention, there are twomanners to update the route table.

The first manner is described as follows. In a situation with a centerserver, each super peer holds the connection with the center serverwhich saves the information of all super peers. And the super peerperiodically sends a request for updating the route table to the centerserver, and the center server returns the newest route table to thesuper peer.

The second manner is described as follows. In a situation without acenter server, all of super peers exchange route information with eachother to update each route table.

According to system and method provided by the present invention,multiparty communication can be implemented and the specificallyapplication of the multiparty communication mainly includes thefollowing two patterns.

A conference pattern: after voice processes to every attendee, achairman relays voice of every attendee to other attendees so as toimplement voice communication between multiple users. When anotherattendee want to participate the conference, the attendee searches thechairman firstly, and then establishes a connection with the chairmanaccording to the above mentioned method, then sends its own data to thechairman. Upon processing to the data of the attendee, the chairmanforwards the data of the attendee to others attendee in the conference.And the chairman can mix voices of different attendees, and send themixed data to other attendees.

A peer to peer pattern: a data channel between every two peers isestablished, such as multi-user video. A user directly establishesconnection with each user which has the requirement of datacommunication by using the above mentioned method of the presentinvention, and sends the application data through the connection. Forexample, in a video conference with multiple users, user A expects tosee the video of user B and user C, so user A establishes a data channelwith user B and user C respectively so as to implement multi-user videocommunication.

The foregoing is only preferred embodiments of the present invention andis not for use in limiting the present invention. Any modification,equivalent replacement or improvement made under the spirit andprinciples of the present invention is included in the protection scopethereof.

1. A system for data communication, comprising communication peers whichestablish connections based on network information and implement datacommunication through the connections, wherein the system comprises atleast two super peers, and every super peer is configured to savenetwork information of a communication peer which is logically closestto the super peer, forward messages among the super peers and send thenetwork information of a destination communication peer to anorigination communication peer.
 2. The system according to claim 1,wherein the super peers comprise a part of the communication peers. 3.The system according to claim 2, wherein the super peer comprises apublic network communication peer or hybrid network address translationcommunication peer.
 4. The system of claim 1, wherein the super peercomprises a communication peer whose bandwidth is larger than or equalto a preset bandwidth, and whose online time length is larger than orequal to a preset online time length.
 5. The system of claim 1, whereinthe system further comprises: a center server, collecting networkinformation of every super peer, and instructing every super peer toupdate a route table of the every super peer.
 6. A method for datacommunication, comprising: sending, by an origination communicationpeer, a query for a destination communication peer to a first super peerwhich is physically closest to the origination communication peer;searching a second super peer which is logically closest to thedestination communication peer from the first super peer; sending, bythe second super peer, saved network information of the destinationcommunication peer to the origination communication peer; establishing,by the origination communication peer, a connection to the destinationcommunication peer based on the network information of the destinationcommunication peer, transmitting data for data communication over theconnection.
 7. The method according to claim 6, further comprising:before sending the query for the destination communication peer to thefirst super peer, assigning a part of communication peers as superpeers, wherein every super peer saves route in formation of theconnected communication peers or super peers; logging in, by acommunication peer, the super peer which is physically closest to thecommunication peer; forwarding in turn, by every super peer, from thesuper peer which is physically closest to the communication peer,network information of the logged communication peer according to savedroute information, until the network information of the loggedcommunication peer is forwarded to and recorded in the super peer whichis logically closest to the logged communication peer.
 8. The methodaccording to claim 7, wherein the assigning a part of communicationpeers as super peers comprises: reading information of the communicationpeer in network in turn; if it is determined that the currentcommunication peer is a public network peer or a hybrid network addresstranslation peer according to the read information of the currentcommunication peer, and bandwidth and online time length of the currentcommunication peer are larger than or equal to a preset bandwidth andonline time length, assigning the current communication peer as a superpeer; otherwise determining the current communication peer is not asuper peer, and returning to the process of reading information of thecommunication peer in network to perform the determining processes toother communication peers.
 9. The method according to claim 7, whereinthe super peer which is physically closest to the communication peer iscalled a physical super peer of the communication peer; and the superpeer which is logically closest to the communication peer is called alogical super peer of the communication peer; and the processes oflogging in, by a communication peer, the super peer which is physicallyclosest to the communication peer; and forwarding in turn, by everysuper peer from the super peer which is physically closest to thecommunication peer, network information of the logged communication peeraccording to the saved route information, until the network informationof the logged communication peer is forwarded to and recorded in thesuper peer which is logically closest to the logged communication peercomprises: logging in, by the communication peer, the physical superpeer of the communication peer after logging in a communication system,and sending the network information of the communication peer to thephysical super peer of the communication peer; searching, by thephysical super peer, an ID which is closest to the ID in the networkinformation of the logged communication peer from the saved IDs;forwarding the network information of the logged communication peer tothe super peer corresponding to the closest ID; repeating the forwardingprocess, by the super peer to which the network information isforwarded, until the network information is forwarded to and saved inthe logical super peer of the communication peer.
 10. The methodaccording to claim 6, wherein the super peer which is physically closestto the communication peer is called a physical super peer of thecommunication peer; and the super peer which is logically closest to thecommunication peer is called a logical super peer of the communicationpeer; and the process of sending, by an origination communication peer,a query for a destination communication peer to a first super peer whichis physically closest to the origination communication peer; searching asecond super peer which is logically closest to the destinationcommunication peer from the first super peer; sending, by the secondsuper peer, saved network information of the destination communicationpeer to the origination communication peer comprises: sending, by theorigination communication peer, the query to the physical super peer ofthe origination communication peer, wherein the query includes the ID ofthe destination communication peer; searching, by the physical superpeer, an ID which is closest to the ID of the destination communicationpeer from the saved IDs; forwarding the query to the super peercorresponding to the closest ID; repeating the forwarding process by thesuper peer to which the query is forwarded, until the query is forwardedto and saved in the logical super peer of the destination communicationpeer; sending, by the logical super peer of the destinationcommunication peer, the saved network information of the destinationcommunication peer to the origination communication peer.
 11. The methodaccording to claim 6, wherein the establishing, by the originationcommunication peer, connection to the destination communication peercomprises: sending, by the origination communication peer, a connectionrequest directly to an internal network IP address and a port number ofthe destination communication peer based on the acquired internalnetwork IP address and port number of the destination communicationpeer; and establishing the connection between the originationcommunication peer and the destination communication peer.
 12. Themethod according to claim 6, further comprising: performing a SimpleTraversal of User Datagram Protocol through Network Address Translators,STUN, test to a communication peer, acquiring an external IP address anda port number of the communication peer, and adding the external IPaddress and port number of the communication peer into the networkinformation of the communication peer; and wherein the establishing bythe origination communication peer a connection to the destinationcommunication peer comprises: sending directly, by the originationcommunication peer, a connection request to the external IP address andport number of the destination communication peer based on the acquiredexternal IP address and port number of the destination communicationpeer; and establishing, by the origination communication peer, theconnection with the destination communication peer.
 13. The methodaccording to claim 6, further comprising: performing an STUN test to acommunication peer, acquiring an external IP address, a port number anda network type of the communication peer, and adding the external IPaddress, port number and network type into the network information ofthe communication peer; and wherein the establishing by the originationcommunication peer a connection to the destination communication peercomprises: determining, by the origination communication peer, aconnection mode according to the network type of the originationcommunication peer and the network type of the destination communicationpeer: if one party of communication is a public network peer and theother part of communication is a network address translation peer,initiating, by the public network peer, the connection; if the twoparties of communication are neither public network peers nor thenetwork address translation peers, sending, by the originationcommunication peer, a traversal request to the physical super peer ofthe destination communication peer; forwarding, by the physical superpeer, the traversal request to the origination communication peer andthe destination communication peer respectively; sending, by theorigination communication peer and the destination communication peerrespectively, User Datagram Protocol, UDP, traversal packets to theexternal IP address and port number of each other, so as to establishthe connection between the origination communication peer and thedestination communication peer.
 14. The method according to claim 6,wherein the establishing by the origination communication peer aconnection to the destination communication peer comprises: establishingthe connection via an internal network direct-connection, an externalnetwork direct-connection and a traversal of UDP at the same time; andwhen the connection is established by any one of the three connectionmethods, stopping establishing the connection in the other two methods.15. The method according to claim 14, further comprising: if failing toestablish the connection via any one of the three connection methods,sending, by the origination communication peer, a request for searchinga relay seed to super peers connected with the origination communicationpeer; acquiring, by the super peers, information of the communicationpeer which can forward data via a center server or other super peers,and returning the information acquired to the origination communicationpeer; establishing, by the origination communication peer, a relaychannel based on the information from the super peer to establish theconnection to the destination communication peer.
 16. The methodaccording to claim 15, wherein the establishing relay channel by theorigination communication peer comprises: establishing a number of relaychannels in which one of the relay channels is regarded as a mainchannel, others are regarded as backup channels; and the method furthercomprises: switching data communication to the backup channel if themain channel of data communication is disconnected.
 17. The methodaccording to claim 6, wherein the super peer performs forwardingaccording to router information saved, and the method further comprises:updating the route information of every super peer.
 18. The methodaccording to claim 17, wherein the updating the route informationcomprises: sending periodically, by the super peer, a request forupdating a route table to the center server; returning, by the centerserver, the newest route table to the super peer.
 19. The methodaccording to claim 17, wherein the updating the route informationcomprises: exchanging, by all of the super peers, the route informationwith each other to update the route table in each super peer.